mk: fix link of combined shared library using CC

mk: fix link of combined shared library using CC

If we set EXTRA_CFLAGS=-O0, build fails with following error:
	/usr/bin/ld: test: hidden symbol `mknod' in /usr/lib64/libc_nonshared.a(mknod.oS) is referenced by DSO

Fix: link combined shared lib using CC if LINK_USING_CC is enabled.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
[Thomas: remove change to rte.lib.mk]
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>